While not important for VSD there have been reports for a while that exiting kleopatra with active asserts results in an assert being hit: https://bugs.kde.org/show_bug.cgi?id=450824 and if there is no assert a null pointer deref would follow some lines later.

To me it seems that the code asserts if the context is not found. This is indeed a sign that something incorrect is happening here. I don't know. I can't reproduce it by just closing kleopatra with running jobs active. Since it seems to be only on shutdown it would be ok for me to just fix the symptom and Return if the context is not found but I would prefer to understand how this can happen.